1991 Fiscal Year Final Research Report Summary
THE ROLE OF ENDOTHELIUM-DERIVED CONSTRICTING FACTOR(ENDOTHELIN) IN THE PATHOGENESIS OF CEREBRAL VASOSPASM
| Project/Area Number |
01480349
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Cerebral neurosurgery
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| Research Institution | UNIVERSITY OF TOKYO |
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Principal Investigator |
SASAKI Tomio UNIVERSITY OF TOKYO, NEUROSURGERY ASSISTANT PROFESSOR, 医学部(病), 講師 (10134561)
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| Co-Investigator(Kenkyū-buntansha) |
IDE Katsuhisa UNIVERSITY OF TOKYO, NEUROSURGERY DOCTOR ASSISTANT, 医学部(病), 助手 (90232420)
ITO Shouichi UNIVERSITY OF TOKYO, NEUROSURGERY DOCTOR ASSISTANT, 医学部(病), 助手 (50223152)
MORIMOTO Tadashi UNIVERSITY OF TOKYO, NEUROSURGERY DOCTOR ASSISTANT, 医学部(病), 助手 (20230154)
NAKAGOMI Tadayoshi UNIVERSITY OF TOKYO, NEUROSURGERY DOCTOR ASSISTANT, 医学部(病), 助手 (90198052)
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| Project Period (FY) |
1989 – 1991
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| Keywords | SUBARACHNOID HEMORRHAGE / CEREBRAL ANEURYSM / CEREBRAL VASOSPASM / ENDOTHELIN / ENDOTHELIAL CELLS / ENDOTHELIUM-DERIVED CONSTRICTING FACTOR / CEREBRAL BLOOD FLOW |
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| Research Abstract |
(1)Endothelin(ET-1) at concentrations of 10^<-12>-3XlO^<-8>M elicited dose-dependent contractions of canine, rabbit and monkey basilar arteries in vitro. The maximum tension was larger than that induced by 4OmM KCl.
(2)ET-1-induced contarction was activated in the canine basilar artery exposed to subarachnoid hemorrhage(SAH).
(3)An intracisternal injection of 6-1.2X10^<-12>mol/kg of ET-1 caused biphasic contraction of the canine basilar artery lasting for more than 24 hours. The initial phase of the contraction accompanied remarkable changes in vital signs such as an acute rise of blood pressure, bradycardia and respiratory arrest.
(4)ET-1 was injected into the cisterna magna of cats and rCBF was measured by the hydrogen clearance method before and every 30 minutes for 180 minutes after the injection. ET-1(10^<-11>moland 10^<-9>mol) induced a significant decrease in rCBF. The effects of ET-1 on rCBF were mediated, at least in part, by Ca^<2+>, because pretreatment with intracisternally injected nicardipine prevented the changes.
(5)Plasma levels of ET-1 were measured in SAH patients, Concentrations of plasma ET-1 in SAH patients with va sospasm were a little higher than those in SAH patients without vasospasm.
(6)The effects of a specific antagonist for ET-1 receptor(BQ-485) on the occurrence of vasospasm were examined in the canine SAH models. Pretreatment of SAH dogs with BQ-485 decreased the degree of angiographic vasospasm by about 15% on Day 7.
These results indicate that ET-1 produced in cerebrovascular endothelium contpibute to the occurrence of vasospasm at least in part, although it is not a main causative factor.
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